Pneumatic toggle devices provided with adjustable fulcrums



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l, 1956 A. A. MARKSON 2,773,257

PNEUMTIC TOGGLE DEVICES PROVIDED WITH ADJUSTABLE FULCRUMS Filed Nov. '7, 1955 gg 4 46 jg. 7 2320 j;

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INVENTOR. ALJ-TRE@ A MAR/50N BY g United States Patent PNEUMATIC TOGGLE DEVICES PROVIDED WITH ADJUSTABLE FULCRUli/IS Alfred A. Marlrson, Pittsburgh, Pa.,` assigner to Hagan Corporation, Pittsburgh, Pa., a corporation ot Penn- Sylvania Application November 7, 1955, Serial No. 545,231

6 Claims. (Cl. 137-620) This invention relates to pneumatic toggles of the type in which the sending or output pressure is either zero or ay maximum. This application is a continuation-in-part of my copending application, Serial No. 157,272, liled August 21, 1950, now Patent No. 2,756,774.

An object of this invention is to provide a pneumatic toggle having a valve which is toggled either to closed or to open position or vice versa, so that the output pressure of the valve is either at zero gauge pressure or at a maximum gauge pressure.

Another object of the invention is to provide a pneumatic toggle having a beam mounted on a fulcrum which is adjustable along the beam, a valve actuated by the beam, means for exerting a fixed but adjustable torce on the beam for normally urging it in a direction in which the valve is closed, means for exerting a force on the beam in excess of the urging means force for actuating the valve from its closed position, and means responsive to the output pressure of the valve as it opens, for actuating the beam with toggle action to a position in which the valve output pressure is a maximum.

A further object of the invention is to provide a pneumatic toggle in which the toggle action thereof may be adjusted and modified.

Other objects and features of the invention will be apparent to those of ordinary skill in the art to which the invention pertains from the following description taken in conjunction with the accompanying drawings.

In the drawings:

Figure l is a view partly in side elevation and partly in vertical longitudinal section of a pneumatic toggle arranged and constructed in accordance with an embodiment of the invention;

Fig. 2 is a modiiied form of the pneumatic toggle; and

Fig. 3 is a View in section taken on line III-III of Fig. l showing details of the fulcrum and its relation to the beam.

In Fig. l of the drawings a pneumatic toggle 1 is illustrated that comprises a beam 2 provided with a fulcrum 3 supported by frame members 4 and 5, a plurality of pressure receiving units or members A, B and C and a pressure receiving and sending unit or member D. As will be shown infra, pressure receiving unit B is optional and may or may not be used according to the requirements of a particular case.

The beam 2 comprises spaced parallel members 7 and 8, being spaced by means of spacer blocks 9 and 10 located between members 7 and 8 at their opposite ends. The beam members 7 and 8 and the spacer blocks 9 and 10 are secured together by means of pins 11.

The frame members 4 and 5 as shown are spaced from each other, being respectively, above and below the beam members '7 and 8, as shown, and maintained in spaced relation by spacer blocks 12 and 13 located between the frame members at the opposite ends thereof as shown. The frame members and the blocks are rigidly secured together by means of screws 14.

Patented Nov. 13, 1956 "ice Block 13 may be provided with tapped holes 16 to accommodate cap screws 17 whereby the: device 1 may be secured to a panel or support member 18.

The fulcrum 3 comprises a roller 19 through which an axle 20 extends. The axle is supported by blocks 21 and 22 portions of which extend inwardly between the frame members 4 and 5 as shown. The axle 20 and the members 21 and 22 are retained and secured by means of nuts 23. The blocks 21 and 22 are clamped against the frame members 4 and 5 by the nuts to hold the fulcrum in any predetermined position to which it is adjusted.

In the form of the toggle illustrated in Fig. l pressure receiving units A and B operate at a distance L1 from the fulcrum 3 and units C and D operate on the beam at a distance L2 from the fulcrum. The relay is so constructed that the distance L1 should always be slightly greater than L2. To provide for such. a setting of the fulcrurn that the length of lever arm L1 is greater than lever arm L2 an adjustable stop 25 is provided. As shown, this stop is disposed on the lleft-hand side of the supporting block 22 and is provided with elongated slots 26 and screws 27 whereby the stop may be secured to the beam members 7 and 8 in any adjusted position. When the stop 25 is in the position shown in Fig. l, lever arm L1 is slightly greater than lever arm L2. By moving the fulcrum supporting blocks 21 and 22 to the right as shown in Fig. l, the blocks are moved away from the stop 25. The stop 25 can be adjusted to engage the blocks over a distance equal to the length of the slots 26. Thus it is assured that lever arm L1 will always be greater than L2, in the speciiic case shown.

The pressure receiving unit A comprises a bonnet 29 and a diaphragm 3b the marginal edge of which is clamped between the bonnet and frame member 5, the frame member 5 being recessed to accommodate the marginal edge or rim of the diaphragm as shown Thus the space between the bonnet and the diaphragm form a pressure receiving chamber 31.

The central portion of the diaphragm is clamped between the head of a bolt 32 and a washer 33, the washer being squeezed against the diaphragm by means of a nut 34. The end of the bolt 32 terminates in a reduced portion 35 that is received in an aperture 36 in beam member 8. The force developed by pressure admitted to chamber 31 is transmitted by the bolt to the beam and the force acts at distance L1 from the fulcrum 3.

Unit B is similar to unit A; therefore, corresponding parts are identified by the same reference characters with primes affixed.

Unit C comprises a bonnet 38 and a diaphragm 39, the marginal edge of which is clamped between the bonnet and frame member 4, the frame member being recessed to receive the marginal edge of the diaphragm as shown. The space Within the bonnet is closed by the diaphragm to form a pressure receiving chamber 4i). The central portion of the diaphragm is clamped between the head of a bolt 41 and a washer 42, the clamping pressure being supplied by a nut 43. The head of the bolt is also provided with a boss 44 to which a spring 45 is secured by means of a clamp 46. The upper end of the spring is secured to a vertically traveling nut 47 that operates on a screw 48 threaded into the upper or closed end of a cylinder 49. The lower end of the cylinder is provided with an annular flange whereby it may be secured to the top of the bonnet as shown. The top of the bonnet 38 is provided with an opening through which the spring extends. The spring 45 exerts an upward force on the diaphragm 39 and that force may be designated FS. Pressure is supplied to the chamber 40 through a pipe 50 and that pressure is the one which determines whether the to a maximum pressure output.

The bolt 44 as shown has a reduced end portion that is received in an aperture in the right hand of the beam so that the net force produced by the pressure acting on the diaphragm 39 and the spring `force FS acts on the beam at a distance L2 -from fulcrum 3.

The pressure receiving unit D comprises a bonnet 52 and a diaphragm S3 the marginal edge of which is clamped between the bonnet and the frame member 5, the frame member being provided with an annular recess for receiving the marginal edge of the diaphragm as shown. The central portion of the diaphragm is clamped between the head of a bolt 54 and a washer 55 by means of a nut S6. The bolt as shown is provided with an exhaust bore 54 that terminates in an aperture 57 in beam member 3. The opposite end of the bore S4 terminates in an exhaust valve port seat 5d. Unit D also includes a Valve stem S9 one end of which is disposed to control the exhaust port seat 58. The valve stem 59 is provided at its opposite end with a valve 60 arranged to control an inlet port el to which a pipe 62 is connected for supplying pressure of constant valve to unit B and to a sending line. Valve stern 59 is normally urged towards its inlet port seat 61 by means of a light compression spring 63.

When valve stem 59 is in neutral position both the exhaust and the inlet ports are closed. When the beam tilts clockwise the exhaust port is held closed while valve 60 is lifted ol the inlet port. If the beam tilts counterclockwise from the neutral position the valve 60 closes on the inlet port but is disengaged from the exhaust port so that pressure medium Within the Ibonnet 52 is exhausted through the bore 54.

Bonnet 52 is provided with an outlet port to which a sending pipe 64 is connected. That pipe, it will be understood, will carry pressure to some appropriate device at a location either near or remote, and will also exhaust pressure `from that device through the pipe 64. Bonnet 52 is also connected by a pipe 65 to the chamber 31 of unit A.

In the specific form shown in Fig. l, the diaphragms of units A, B, C `and D may have equal or unequal areas. As shown the areas of these diaphragms are equal and for convenience may be considered to be of unit area. Therefore, the force exerted by the respective diaphragms on the beam will be proportional to the unit pressure supplied to the chambers with which they are associated. For example, if the pressure in chamber 31 is ten pounds per square inch gauge and the area of the diaphragm is one square inch the force exerted by the diaphragm is ten pounds.

rl`he pressure supplied to unit A may be considered pressure Pi, the pressure supplied to the diaphragm of unit B as pressure P2, and the pressure supplied to chamber 4G of unit C as pressure P3 and the pressure developed in unit D may be regarded as pressure P4. Since units A and D Vare interconnected by the pipe 65 it follows that the pressures in units A and D are equal; there- :fore Pi and P4 are equal.

lr" it be assumed that the pressure P2 is zero, the spring tension in spring 45 is say ten pounds and that the pressure P3 is Zero, then it follows that beam 2 will be tilted counterclockwise from neutral; therefore the pressure in units A and D will be Zero because the inlet valve 6) is closed. If however the pressure P3 is increased to a value where it slightly exceeds the spring force FS of spring 45, there will be a force effective to tilt beam 2. clockwise about its fulcrum in which event the exhaust port 58 is closed and valve 60 is lifted off its valve seat whereby pressure is admitted from the supply pipe 62 into the chamber of bonnet 52. The moment the pressure enters that chamber it is transmitted to the chamber 31 of unit A. The turning moment developedy by unit A is greater than the counter-turning moment developed by the diaphragm of unit D because the lever arm L1 is greater than lever arm L2. Therefore, the net turning force acting on the beam is such as to tilt the beam clockwise quickly whereby maximum pressure is admitted to the chamber of unit D and to the chamber of unit A. In that case the toggle is quickly toggled from a condition where the output pressure P4 is zero to a condition where the output pressure P4 is maximum or equal to the pressure in the supply pipe 62. The toggle device will remain in the maximum pressure output position so long as the pressure P3 exceeds the oppositely acting spring force of spring 45. As the pressure P3 decreases a condition will be reached where the force of the pressure P3 and the force of the spring are equal. As soon as the pressure P3 has decreased slightly below that value the force of the spring 45 will exceed the net turning moments exerted by diaphragms 53 and 30 about the -fulcrum so that the beam will be tilted counterclockwise whereupon the valve 60 is seated and the exhaust port 5S is opened to exhaust the pressure from units A and D. Thus the device is toggled from maximum output pressure to zero output.

It the length of lever arm L1 is gradually increased or increased beyond the point where it is only slightly greater than L2, it will be apparent that the band of pressure change in pressure P3 required to cause the device to togggle from maximum pressure loutput position to minimum pressure output is widened.

The same effect can be obtained by having the lever arms L1 and L2 equal and making the diaphragm 30 of unit A large compared to the area of diaphragm 53. If the area of diaphragm 30 is considerably greater than the area of diaphragm 53, lever arm L1 may be shorter than the lever arm L2. The extreme relationship between relative sizes Would occur when the area of the diaphragm 53 is zero as where no diaphragm is used. Such a case is represented by the modification of Fig. 2.

In the modification of Fig. 2, the pneumatic toggle 1 is similar in all respects to the toggle 1 with the exception that unit D is omitted and an escapement valve 70 is employed in lieu of the poppet valve embodied in unit D; therefore similar and corresponding parts of the device of Fig. 2 are indicated by the same reference characters with primes aflxed. The diaphragms of units A and B act on beam 2 at a distance L1 from the fulcrum 3 and the point `of engagement between the diaphragm of unit C' and the beam is at a distance L2 from the fulcrum. As will be shown infra, the device will toggle whether the lever arm L1 is greater than, equal to, or less than the lever arm L2. The beam 2. as shown operates the escapement valve 70. The escapement valve comprises a body 71 having a valve 72 therein the respective opposite ends of which are tapered and control an inlet port 73 and an exhaust port 74. The inlet port 73 is connected to a supply pipe 75 to which compressed air at constant pressure is supplied. The valve 72 is provided with a stern 76 that is secured to a tongue or linger 77 formed as an integral part of a spacer block 10A at the right-hand ends of beam members 7 and 8. The tongue 77 extends through an aperture 79 in the frame spacer block 12. The stem 76 is Vsecured to the tongue 77 so that as the beam tilts valve 72 is actuated towards the inlet port seat 73 or towards the exhaust port 74 depending upon the net turning moments acting on the beam.

If the pressure P3 supplied to unit C is zero the force of spring 45 actuates beam 2' counterclockwise to a position in which the inlet port seat is closed and the exhaust port 74 is wide open. In that event the pressure in the sending line 80 and in unit A will be Zero or minimum. When the pressure P3 supplied tothe unit C exceeds the oppositely actin-g spring force FS, beam 2 tilts clockwise in which event the exhaust port seat 74 is closed and the inlet port 73 is opened whereby pressure is admitted to unit A. As soon as the pressure is receivedby unit A the turning force developed by the diaphragm actuates the beam and the valve 72 to the maximum pressure output position. The toggle will remain in its maximum output position until the pressure P3 is reduced to such a value below the spring force FS that the turning force of the spring will be greater than the opposed turning force of the diaphragm of unit A. When that condition occurs, beam 2 is tilted counterclockwise and valve 72 moved to the position where the inlet port 73 is closed or so restricted that the pressure in unit A' is decreased. As the pressure in unit A decreases, the force of the spring becomes more and more effective until the inlet port seat 73 is fully closed and the exhaust port opened wide. This toggle action from maximum to minimum pressure output, picks up momentum as the pressure in unit A decreases.

By adjusting the length of lever arm L1 relative to lever arm L2 the toggle band may be made wide or narrow. The band becomes wider as L1 is increased with respect to L2 and it becomes narrower as Li and L2 are equal or L2 is made `greater than L1.

From the foregoing description it will be apparent that a pneumatic toggle is provided in which the valve thereof is actuated either to a Zero output position or to a maximum output position and that the toggle band, that is the pressure change in the pressure P3 required to cause the device to toggle from maximum output to zero output, can be `adjusted by adjusting the relative lengths of the lever arms L1 and L2.

It also should be apparent from the foregoing that changes in the operating characteristics of the toggle device may be made by selecting diaphragm areas that will produce a given operating characteristic.

If a pressure P2 is supplied to units B or B', the effect of the turning moments produced by those pressures will be additive with respect to the force of the springs 45 or 45'. In other words, the equivalent eifect of using a set but adjustable pressure in units B or B' is to change the spring tension 45. The pressure supplied to the units B and B may also be used to effect toggling of the devices from maximum output position to zero output position at Will, as in the case where the pressure Pa might not have decreased in the normal course of events to that value at which the device would toggle to the off position. In that event increasing pressure P2 will supply the additive force required.

Having thus described the invention, it will be apparent to those of ordinary skill in the art to which the invention pertains that various changes yand modifications may be made in the illustrated embodiments thereof without departing from either the spirit or the scope of the same.

Therefore, what is claimed as new and desired to be secured by Letters Patent is:

l. A pneumatic toggle device comprising a beam, a double acting fulcrum for said beam, a valve actuated by said beam from Zero to maximum output positions and vice versa, a pressure receiving member having a chamber and a diaphragm responsive to pressure in said chamber, means connecting said chamber to the output of said valve, means connecting said diaphragm to said beam at a distance L1 from the fulcrum, a second pressure receiving member having a pressure receiving chamber and a diaphragm responsive to pressure in said chamber, the diaphragm of said second chamber being connected to exert a force on said beam at a distance L2 from the fulcrum, the turning moments of the said diaphragms being in the same direction about the fulcrum, and adjustable yielding means in the chamber of said second pressure receiving member for exerting a predetermined force in opposition to the force of pressure on said diaphragm, the second chamber being disposed to receive a variable pressure whereby, when the force of said variable pressure on said second diaphragm is less than the opposing force of said yielding means, the

valve is actuated to one of its output positions and when the -force of the pressure exceeds that yielding means force, the valve is actuated to its other pressure output position.

2. A pneumatic toggle as in claim 1 in which the force of the yielding means urges the beam to a position in which the valve is in zero output position when the force of the pressure acting on said second member diaphragm is less than the spring force, and when the force de- Veloped by said pressure exceeds the spring force, pressure is admitted to the chamber of the iirst pressure receiving member whereby the beam is toggled to a position where the output of the valve is a maximum.

3. A pneumatic toggle as in claim l in which a third pressure receiving unit is provided, said third unit having a chamber and a diaphragm exposed to pressure in the chamber and connected to said beam at a distance L1 from the fulcrum and in opposed relation to the diaphragm of the iirst pressure receiving member, said third chamber being adapted to receive a set point pressure for modifying the force of said yielding means on the beam.

4. A pneumatic toggle device comprising a beam, a double-acting fulcrum for said beam disposed between the ends thereof, a pressure-receiving unit mounted on each side of said fulcrum, said units acting `on said beam at distances L1 and L2, respectively, from said fulcrum, stop means for the fulcrum so arranged that distance Lr is always greater than distance L2, said pressure receiving units exerting opposed turning forces on the beam, and a pressure-actuated toggling unit mounted on one side of the fulcrum in opposed relation to one of said units, and acting on said beam at a distance L2 from the fulcrum, each of said pressure-receiving units comprising a bonnet having an open side facing said beam, and a flexible diaphragm secured across said open side to form in its associated bonnet a pressure-tight chamber, said diaphragms being operatively connected to said beam and exerting opposed turning forces thereon with respect to said fulcrum, a valve actuated by said beam for supplying a medium under pressure to said pressure-receiving units, said valve being normally closed, said toggling unit comprising a bonnet having an open side facing said beam, a diaphragm across said opening forming in said bonnet a pressure-tight chamber, said toggling unit diaphragm having means for applying a force to said beam at a point directly opposite to the point where the adjacent pressure-receiving unit acts on said beam, a pressuretight member supported by said bonnet in pressure-tight relationship therewith, said member having communication with the interior of the bonnet, and having therein a yieldable tension member connected to the diaphragm and exerting a predetermined force thereon in a direction to urge the diaphragm out of force-exerting relation with said beam, said toggling unit diaphragm acting on said beam to exert a turning force thereon to unbalance said beam and actuate said valve to open ponition when the force of pressure acting on said toggling unit diaphragm exceeds the opposing force of said tension member.

5. A pneumatic toggle device according to claim 4 in which the diaphragm of said pressure-receiving units are equal.

6. A pneumatic toggle device comprising a beam, a double-acting fulcrum for said beam disposed between the ends thereof, a pressure-receiving unit mounted at each side 0f said fulcrum, said units being connected to receive the same pressure and acting on said beam in opposed relation at distances L1 and L2, respectively, from said fulcrum, means for securing the fulcrum in a position where the distance L1 is greater than the distance L2, and a pressure-actuated toggling unit on one side of the fulcrum in opposed relation to one of said units and acting on said beam at a distance L2 from the fulcrum, each of said pressure-receiving units comprising a bonnet having an open side facing said beam, and a flexible diaphragm secured across that open side to form, in its associated bonnet, a pressure-tight chamber, said diaphragms being operatively connected to said beam to exert opposing forces thereon and tending to turn said beam in opposite direction about said fulcrum, said toggling unit comprising a bonnet having an open side facing said beam, a diaphragm across said open side forming in said bonnet a pressure-tight chamber, and means urging said diaphragm in a direction opposing the force of the pressure acting thereon, a valve embodied in the pressure-receiving unit that is directly opposed to said toggling unit, said Valve being normally closed and comprising a valve body secured to said bonnet and communicating with the chamber therein, said bonnet having an inlet port provided with a seat, a valve stem in said body having a valve element adjacent one end thereof disposed to seat on the inlet port seat, said diaphragm having an exhaust port and a seat therefor, the opposite end of said valve stem being disposed to seat in the exhaust port seat, both valve ports being closed by said stem when the beam is a neutral position, the inlet port being open when the force of pressure on the toggling unit diaphragm exceeds the restraining force acting thereon by said urging means, whereby the pressure in said receiving units is increased to a value equal to that of the supply source connected to the Valve when the pressure of the toggling unit diaphragm exceeds the force of the urging means thereon, the area of the diaphragm associated with saidpressurereceiving unit embodying said valve being no greater than the area of the diaphragm associated with said other pressure-receiving unit.

References Cited in the le of this patent 'UNTED STATES PATENTS 2,756,774 Markson July 31, 1956 

